Lifetime Prediction for Structural Elements of a Tamman Vacuum High-Temperature Furnace by Means of Mathematical Models

A mathematical structural model of a Tamman vacuum high-temperature electric furnace with a heater in the form of a coal or graphite pipe and thermal insulation in the form of graphite cylinder shields is developed and implemented in the Simulink software package. The thermal resistance of the thermal conductivity of graphite shields, which is traditionally neglected in the calculation of widespread thin metal shields, was taken into account in the simulation of thermal processes. Also, the model takes into account the mass flow of the material of the elements of the furnace structure (the speed of the mass flow depends on the temperature and pressure in the working space), causing a change of the size and, correspondingly, the coefficients of the heat transfer caused by the radiation of the elements of the structure. The temperature regime of separate structural elements (heaters, shields, etc.) is analyzed both for a constant supply voltage of heaters and for the case in which a closed temperature control system is used. The influence of the temperature regime of structural elements on the wear of heating elements and shields is shown.